Several air systems having various features are generally known for conveying bottles. U.S. Pat. No. 4,283,370 to Danler comprises a plurality of air slots or jets, in vertically oriented conveying channel side walls, for issuing air impinging on neck portions of the bottles.
U.S. Pat. No. 4,822,214 to Aidlin comprises a plurality of air directing louvers in the top and side walls of an inverted, U-shaped interior channel which receives the neck portion of a container. The louvers convey the container in the direction of the air flow and fill the container with air.
Designs such as these which provide air jets disposed above the neck tracks, or otherwise convey bottles by directing air toward the bottles at a location above their neck rings, are disadvantageous since contaminants in air from the plenum may be introduced into the bottles. This disadvantage may be exacerbated in a design requiring that a relatively large bottle be conveyed by directing air substantially only at a relatively small neck portion of the bottle since conveying such a bottle may necessitate relatively high air pressures. A further disadvantage is friction which may develop between the neck tracks of a conveyor and the neck rings of bottles, requiring increased air pressure to convey bottles and reducing system efficiency. Increases in the air pressure required to convey bottles may lead to increases in the contamination of bottles by plenum air.